IEC 60539-1:2002

INTERNATIONAL IEC
STANDARD
60539-1
QC 430000
First edition
2002-02
Directly heated negative temperature
coefficient thermistors –
Part 1:
Generic specification
Thermistors à coefficient de température négatif
à chauffage direct –
Partie 1:
Spécification générique
Reference number
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INTERNATIONAL IEC
STANDARD
60539-1
QC 430000
First edition
2002-02
Directly heated negative temperature
coefficient thermistors –
Part 1:
Generic specification
Thermistors à coefficient de température négatif
à chauffage direct –
Partie 1:
Spécification générique
 IEC 2002  Copyright - all rights reserved
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– 2 – 60539-1  IEC:2002(E)
CONTENTS
FOREWORD .………………………………………………… 4

1 General. 5

1.1 Scope . 5

1.2 Normative references. 5

2 Technical data .7

2.1 Units, symbols and terminology . 7

2.2 Definitions . 7
2.3 Preferred values . 15
2.4 Marking. 15
3 Quality assessment procedures . 16
3.1 General. 16
3.2 Primary stage of manufacture . 16
3.3 Structurally similar components . 16
3.4 Qualification Approval procedures . 16
3.5 Quality conformance inspection . 17
3.6 Certified test records of released lots. 17
3.7 Delayed delivery . 17
3.8 Release for delivery under qualification approval before the completion of
Group B tests. 17
3.9 Alternative test methods . 18
3.10 Unchecked parameters . 18
4 Test and measurement procedures . 18
4.1 General. 18
4.2 Standard atmospheric conditions for testing. 18
4.3 Drying and recovery. 19
4.4 Visual examination and check of dimensions . 19
4.5 Zero-power resistance . 19
4.6 B-value or resistance ratio . 20
4.7 Insulation resistance (for insulated types only). 20
4.8 Voltage proof (for insulated types only). 21
4.9 Resistance/temperature characteristic . 22

4.10 Dissipation factor (δ). 22
4.11 Thermal time constant by ambient temperature change (τ ) . 23
a
4.12 Thermal time constant by cooling after self-heating (τ ) . 23
c
4.13 Robustness of terminations (not applicable to surface mount thermistors) . 24
4.14 Resistance to soldering heat. 25
4.15 Solderability. 26
4.16 Rapid change of temperature. 27
4.17 Vibration . 28
4.18 Bump. 28
4.19 Shock . 29
4.20 Free fall (if specified in the detail specification). 29
4.21 Thermal shock (if specified in the detail specification). 29
4.22 Climatic sequence . 30
4.23 Cold (if required by the sectional specification) . 31

60539-1  IEC:2002(E) – 3 –
4.24 Dry heat (if required by the sectional specification) . 32

4.25 Damp heat, steady state . 32

4.26 Endurance . 33

4.27 Mounting (for surface mount thermistors only) . 37

4.28 Shear (adhesion) test . 38

4.29 Substrate bending test . 39

4.30 Component solvent resistance . 39

4.31 Solvent resistance of marking . 39

4.32 Salt mist (if required by the sectional specification). 40

4.33 Sealing (if required by the sectional specification) . 40

Annex A (normative) Interpretation of sampling plans and procedures as described
in IEC 60410 for use within the IEC quality assessment system for electronic
components (IECQ). 41
Annex B (normative) Rules for the preparation of detail specifications for capacitors
and resistors for electronic equipment . 42
Annex C (informative) Typical examples of mountings for measurements of directly
heated thermistors . 43

– 4 – 60539-1  IEC:2002(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
DIRECTLY HEATED NEGATIVE TEMPERATURE COEFFICIENT

THERMISTORS –
Part 1: Generic specification
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International
Organization for Standardization (ISO) in accordance with conditions determined by agreement between the
two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60539-1 has been prepared by IEC technical committee 40:
Capacitors and resistors for electronic equipment.
This edition cancels and replaces the first edition of IEC 60539 published in 1976.
The text of this standard is based on the following documents:
FDIS Report on voting
40/1193/FDIS 40/1249/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
Annexes A, B and C form an integral part of this standard.
The committee has decided that the contents of this publication will remain unchanged until
2005. At this date, the publication will be
reconfirmed;
withdrawn;
replaced by a revised edition, or
amended.
60539-1  IEC:2002(E) – 5 –
DIRECTLY HEATED NEGATIVE TEMPERATURE COEFFICIENT

THERMISTORS –
Part 1: Generic specification
1 General
1.1 Scope
This part of IEC 60539 is applicable to directly heated negative temperature coefficient
thermistors, typically made from transition metal oxide materials with semiconducting
properties.
It establishes standard terms, inspection procedures and methods of test for use in sectional
and detail specifications of electronic components for quality assessment or any other
purpose.
1.2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60539. For dated references, subsequent amend-
ments to, or revisions of, any of these publications do not apply. However, parties to
agreements based on this part of IEC 60539 are encouraged to investigate the possibility of
applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of IEC
and ISO maintain registers of currently valid International Standards.
NOTE In the case of
...